Pulp, Paper and Tissue

Wherever you look, paper products are a vital part of our daily lives. Newspapers, magazines, packaging, serviettes, tissues… the list is endless.

Paper is made from logs that are too small for solid wood products or from the bits and pieces left over after sawmilling. The process starts by making pulp from the wood chips, breaking down the wood’s cellulose into fibres using either a mechanical or chemical process. A slurry is made by mixing the fibres with water. Then additives are added, such as sizing agents to give the paper a smooth, even surface, colouring agents and materials for special properties such as waterproofing.

The slurry is spread onto a large belt on the paper machine. When the water is removed, the layer of fibres left looks like rough paper and is called pulp. This pulp continues through a series of steam-heated drying rollers then finally over smooth calendar rolls that give the paper its smooth finish. The paper is wound on to large rollers ready to make into different types of paper.

The main types of paper products can be grouped as follows:

Newsprint
Newsprint is relatively cheap to produce and is used to make items that don’t require durability such as newspapers and telephone directories. They are made from the cheapest type of pulp (using mechanical processes) and recycled paper. Newsprint and magazine papers are usually printed at high speed. To prevent smudging and print spoiling, the ink must be absorbed into the sheet quickly.

Paperboards
Paperboard is white lined or solid white boards used for packaging small items. They are usually printed with a high quality print for customer appeal, e.g. breakfast cereals, cake mixes and display packs for sweets and cosmetics. The board must have a certain amount of stiffness to protect the contents and retain the pack’s shape and have the right surface and ink absorbency to handle high quality printing.

Tissue
Paper tissue is used for making paper towels, wrapping paper, facial tissue, serviettes, toilet tissue and nappies. Tissue papers are usually made of well bleached pulp, treated to improve softness, absorbency and strength. Some forms also have wet strength properties.

Corrugated board
Corrugated boxes are used for the packaging and transport of most materials – from fruit and vegetables to refrigerators and washing machines. Corrugated board has a central corrugated layer which maximises strength and resistance to crushing. The type of outer layer depends on other requirements such as colour and printable surface.

Wrapping and bag
Wrapping and bag papers are used to make multi wall sacks or bags used for cement, fertiliser, kleensaks and paper carry bags. Most of these papers are made from unbleached ‘kraft’ pulps for strength. This is achieved by using pulp with long, well formed fibres evenly laid and criss-crossed. This gives strength, some stretch, resistance to wetting and a smooth surface for printing or labelling.

Whatever the product, from that first cut in the log to the end result, every step of the process depends on people with knowledge, technical skills and good judgement.